From patchwork Wed Nov 8 07:20:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arseniy Krasnov X-Patchwork-Id: 13449634 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2BE1ED266; Wed, 8 Nov 2023 07:27:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=salutedevices.com header.i=@salutedevices.com header.b="R9IREQxx" Received: from mx1.sberdevices.ru (mx1.sberdevices.ru [37.18.73.165]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05E21198; Tue, 7 Nov 2023 23:27:48 -0800 (PST) Received: from p-infra-ksmg-sc-msk01 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id 180C9100023; Wed, 8 Nov 2023 10:27:45 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru 180C9100023 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=salutedevices.com; s=mail; t=1699428465; bh=GboU7QxQo+Iiecc7y5wDkeix0frYFM0ixS3MLnG4nCs=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=R9IREQxxLHd4Y72wNfKVkCCE5pKZPTBYiQK0xYhqp6UjoEUFzoWw2sT9hDS9p5iTG 29HL+TBcNTyXCQ31S+QqgP/wRjnQZ1bvIka/6L1GA/E0w9E/gkW4cUYXcuHR0X8K6T r5bjCLAviw4hgjUcUXfWhr6mqtCe6fyZMNPxTJp/aDX0xkqnfgxSfyyJgEwXT8q/dq aUh2FiwsxufHyUo8fxsO8RmWhrqLdWTQKL0QcWtywZNMsF5ZgFJJq2jbMQRiTTbiQn E+q++1tXcOVO6rh4GqFbuAOEVGJCsfs7EYUkMk0BIv4IxF8xQChyhA2yMoLRq4wV04 uHgchs8maZMrQ== Received: from p-i-exch-sc-m01.sberdevices.ru (p-i-exch-sc-m01.sberdevices.ru [172.16.192.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.sberdevices.ru (Postfix) with ESMTPS; Wed, 8 Nov 2023 10:27:44 +0300 (MSK) Received: from localhost.localdomain (100.64.160.123) by p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.37; Wed, 8 Nov 2023 10:27:44 +0300 From: Arseniy Krasnov To: Stefan Hajnoczi , Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Michael S. Tsirkin" , Jason Wang , Bobby Eshleman CC: , , , , , , Subject: [RFC PATCH v1 0/2] send credit update during setting SO_RCVLOWAT Date: Wed, 8 Nov 2023 10:20:02 +0300 Message-ID: <20231108072004.1045669-1-avkrasnov@salutedevices.com> X-Mailer: git-send-email 2.35.0 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Originating-IP: [100.64.160.123] X-ClientProxiedBy: p-i-exch-sc-m02.sberdevices.ru (172.16.192.103) To p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) X-KSMG-Rule-ID: 10 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Lua-Profiles: 181188 [Nov 08 2023] X-KSMG-AntiSpam-Version: 6.0.0.2 X-KSMG-AntiSpam-Envelope-From: avkrasnov@salutedevices.com X-KSMG-AntiSpam-Rate: 0 X-KSMG-AntiSpam-Status: not_detected X-KSMG-AntiSpam-Method: none X-KSMG-AntiSpam-Auth: dkim=none X-KSMG-AntiSpam-Info: LuaCore: 543 543 1e3516af5cdd92079dfeb0e292c8747a62cb1ee4, {Tracking_uf_ne_domains}, {Tracking_from_domain_doesnt_match_to}, 100.64.160.123:7.1.2;salutedevices.com:7.1.1;127.0.0.199:7.1.2;p-i-exch-sc-m01.sberdevices.ru:5.0.1,7.1.1;lore.kernel.org:7.1.1;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;git.kernel.org:7.1.1, FromAlignment: s, ApMailHostAddress: 100.64.160.123 X-MS-Exchange-Organization-SCL: -1 X-KSMG-AntiSpam-Interceptor-Info: scan successful X-KSMG-AntiPhishing: Clean, bases: 2023/11/08 06:11:00 X-KSMG-LinksScanning: Clean, bases: 2023/11/08 06:10:00 X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 2.0.1.6960, bases: 2023/11/08 04:00:00 #22424297 X-KSMG-AntiVirus-Status: Clean, skipped Hello, DESCRIPTION This patchset fixes old problem with hungup of both rx/tx sides and adds test for it. This happens due to non-default SO_RCVLOWAT value and deferred credit update in virtio/vsock. Link to previous old patchset: https://lore.kernel.org/netdev/39b2e9fd-601b-189d-39a9-914e5574524c@sberdevices.ru/ Here is what happens step by step: TEST INITIAL CONDITIONS 1) Vsock buffer size is 128KB. 2) Maximum packet size is also 64KB as defined in header (yes it is hardcoded, just to remind about that value). 3) SO_RCVLOWAT is default, e.g. 1 byte. STEPS SENDER RECEIVER 1) sends 128KB + 1 byte in a single buffer. 128KB will be sent, but for 1 byte sender will wait for free space at peer. Sender goes to sleep. 2) reads 64KB, credit update not sent 3) sets SO_RCVLOWAT to 64KB + 1 4) poll() -> wait forever, there is only 64KB available to read. So in step 4) receiver also goes to sleep, waiting for enough data or connection shutdown message from the sender. Idea to fix it is that rx kicks tx side to continue transmission (and may be close connection) when rx changes number of bytes to be woken up (e.g. SO_RCVLOWAT) and this value is bigger than number of available bytes to read. I've added small test for this, but not sure as it uses hardcoded value for maximum packet length, this value is defined in kernel header and used to control deferred credit update. And as this is not available to userspace, I can't control test parameters correctly (if one day this define will be changed - test may become useless). Head for this patchset is: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=ff269e2cd5adce4ae14f883fc9c8803bc43ee1e9 Arseniy Krasnov (2): virtio/vsock: send credit update during setting SO_RCVLOWAT vsock/test: SO_RCVLOWAT + deferred credit update test drivers/vhost/vsock.c | 2 + include/linux/virtio_vsock.h | 1 + net/vmw_vsock/virtio_transport.c | 2 + net/vmw_vsock/virtio_transport_common.c | 31 ++++++ net/vmw_vsock/vsock_loopback.c | 2 + tools/testing/vsock/vsock_test.c | 131 ++++++++++++++++++++++++ 6 files changed, 169 insertions(+)